Glucans are polymers of glucose which may be derived from the cell walls of yeast. Yeast glucans containing a beta (1,3)-linked glucopyranose backbone have been known to have biological activity, specifically they have been shown to activate the immune system across kingdom lines.
Neutral beta (1,3) glucan polymers are limited in their utility, for example in foodstuffs and pharmaceutical compositions, because they are not readily soluble in aqueous, physiological media. Attempts to develop soluble beta (1,3) glucans thus far depend upon chemical substitution with charged groups, such as phosphate (see U.S. Pat. No. 4,707,471) or other functional groups such as sulphate, which change the native conformation of the glucan molecules and may alter their biological and pharmacokinetic properties.